1. Field of the Invention
The present invention relates to a system and device for positioning a piece to be machined by a router. The invention also relates to the use a system and device for positioning the piece to be machined.
2. Description of the Related Art
A router is a tool, especially used in the woodworking industry, used for milling out (hollow out) an area in the face of a piece of material (workpiece). Usually the material is wood or metal, but applying the router to other types of materials is also possible. There are several types of routers. Nowadays, most common types are spindle type routers (spindle routers), where a router bit is mounted onto a rotatable spindle of an electric motor.
A typical router set-up includes a frame for supporting the router table. The piece of material to be machined is supported by the table. The table has an opening through which a bit protrudes for machining the material. Different bit sizes and shapes can be used, and the bit is easily exchangeable. The bit is engaged by a collet provided with a clamping mechanism such as a number of clamps or jaws. The collet is part of a rotatable spindle that is connected to a motor drive for rotation. The router collet (and router bit mounted in the mouth of the collet) can be rotated around an axis perpendicular to the router table. Sometimes the collet may be able to move with respect to the table, for example, along the axis of rotation by a depth adjustment tool. In this case, the shape of the cut that is created is determined by the size and shape of the bit (cutter) held in the collet and the height of the bit relative to the upper surface of the router table.
A typical router system also includes a router fence. The router fence is placed on top of the table and is used as a stop along which the workpiece can be guided during the machining thereof to ensure that the proper part of the workpiece is cut away. The router fence is used as a directional tool during the processing of the workpiece.
Three important variables determining the router's work are: 1) the shape of the router bit (the cutter); 2) the height of the router bit (in most cases the router machine is held in a router lift, that allows easy vertical travel); and 3) the distance between the router bit and the fence. The first and second variables have been discussed earlier and can be successfully dealt with. Regarding the first variable, a large variety of different router bit shapes are on the market nowadays, allowing an almost indefinite shape to be routed to the workpiece. In the second variable, variation of the router bit height, determines how much of the wood is actually shaped. The variation may be accomplished by a depth adjustment tool, for example a router lift. The router lift allows the entire router machine to be cranked up or down with great precision, exposing more or less of the router bit above the router table. However, the handling of the third variable remains burdensome and is currently to a large extent a process of trial and error. In particular, where the workpiece needs to be shaped in the middle, setting the fence at the correct distance from the router bit is a challenging process that requires solving two previous problems: dividing by two the width of the workpiece and adding to the result half of the router bit's diameter.
Whereas dividing by two the router bit's diameter is no problem, calculating half the workpiece width is challenging when the width of the workpiece is not an “easy” number such as about 1 in, ¾ in, ½ in. etc. (which happens when the wood is previously planed or sanded down to a “random” width).
The resulting numbers have to be added, but more challenging is measuring the distance from the outer diameter of a given router bit to the face of the fence. Typically, router bits have an irregular shape, with a core and a number of cutters. As such, router bits do not really have an evident outer diameter, except for the actual cutter extremities. This makes the above-mentioned determination of the distance between the fence and the router bit difficult.
Woodworkers are required to do the above-described math and struggle to measure the distance to the fence with the help of a tape measure, set-up blocks or any other measuring device. In this respect, it is noteworthy that woodworkers mostly ensure centering a groove in the board by a second pass through the router with the other side of the wood against the fence. This will effectively ensure exact centering of the groove, but in the process sacrifices the groove's intended width, which mostly defeats the object of the exercise.
Currently, as stated above, there is no technical solution on offer, whether mechanized or by way of a slide rule, or any other method, to position a router fence successfully for the purpose of routing a groove through the centerline of a board.
It is further noteworthy that the result of the above-mentioned calculations is affected by the diameter of the chosen router bit, and that the calculation will have to be repeated at each change of diameter.